This invention relates to magnetic detector instruments, e.g., magnetometers, gradiometers and the like, which may include one or more magnetic sensors of the saturable core (fluxgate) type.
Magnetic sensors of the fluxgate type generally comprise a magnetic core and separate excitation and signal windings. The signal winding may, for example, be disposed on a tubular bobbin or the like, with the core and excitation conductor disposed interiorly of the bobbin.
With instruments using a single sensor, and also with instruments using multiple sensors, the precise axial alignment of the sensor core or cores is critical. For example, in a single-sensor, vector-type magnetometer where the sensor is generally contained in an elongate housing, the core axis should be aligned with the longitudinal axis of the housing. Also, in gradiometers, for example, using a pair of sensors with their excitation conductors connected in series, it is desirable for the core axes to be aligned substantially coaxially or in parallel. (See, for example, assignee's earlier U.S. Pat. Nos. 4,110,689 and 3,961,245.)
Generally, in magnetic detector instruments as described, if the core axis (or axes) is (or are) properly aligned, a uniform output signal will be produced when the instrument is rotated in a uniform magnetic field about the longitudinal axis of its housing. Accordingly, one known method of testing the alignment is to rotate the instrument about the longitudinal housing axis, and detect the output signal. This may then be adjusted, if required, by adjusting the alignment of the sensor core axis or axes.
The present invention is particularly concerned, in one of its aspects, with the manner of mounting a sensor on a circuit board or like support of a magnetic detector instrument so as to facilitate mounting and adjustment of the sensor, and, in another of its aspects, with a fitting for receiving the circuit board or support in an expeditious manner which facilitates rotation of the board about its longitudinal axis when setting the sensor alignment.